\documentclass{standalone}
\usepackage{tikz}
\usepackage{ctex,siunitx}
\setCJKmainfont{Noto Serif CJK SC}
\usepackage{tkz-euclide}
\usepackage{amsmath}
\usepackage{wasysym}
\usepackage{circuitikz}
\usetikzlibrary{patterns, calc}
\usetikzlibrary {decorations.pathmorphing, decorations.pathreplacing, decorations.shapes,}
\ctikzset{bipoles/length=1cm}
\begin{document}
\small
\begin{circuitikz}[>=latex, scale=1.3,european]
  % \useasboundingbox(0.9,0)rectangle(5.1,5);
  % \draw [->](0.05,0)--(2,0)--(3,0)to [R=$W$,-*](3,2)--(2.15,2);

  \draw (1,2.5)--(2,2.5) to [pR,name=hb,-*] (2,0)--(1,0);
  \draw(1,0)--(0,0);
  \draw(1,2.5)--(0,2.5);
  \draw [fill=white](0.06,0) circle (2pt);
  \draw [fill=white](0.06,2.5) circle (2pt);
  \draw[<->] (0.06,0.12)--(0.06,2.38)node[midway,right]{$U$};
  \node at (hb.left) [right=1mm]{$R_1$};
  \node at (hb.right)[right=1mm]{$R_2$};
  \draw (2,0)--(3,0)to[R=$W$](3,0|-hb.wiper)--(hb.wiper);
\end{circuitikz}
\end{document}